As a simultaneous process of corrosion and mechanical wear, tribocorrosion can cause accelerated wear of dental materials during their use. The goal of the doctoral thesis was to obtain information about two environmental effects which affect these materials, i.e. tribocorrosion processes and the quantity of metal ions released onto them. The materials involved were two dental alloys, i.e. NiTi alloy wire, and stainless steel wire, both in simulated saliva. Their corrosion properties were determined by electrochemical methods, whereas their mechanical and microstructural properties, as well as the composition of their oxide layers, were determined by means of various physical and spectroscopic methods. Tribocorrosion tests were used to evaluate the total wear rate and the contributions to total wear. The corrosion properties of the wires in saliva, as well as in saliva with low pH values and in the presence of fluorides, were determined by means of electrochemical methods. It was confirmed that, on the one hand, the NiTi alloy has good repassivation properties, although at low pH values and in the presence of fluorides it undergoes accelerated dissolution. On the other hand it was found that the stainless steel wires had a lower polarization resistance compared to that of the NiTi alloy, as well as a greater tendency to local corrosion, which was determined from the positive hysteresis of the cyclic polarization curve. During the tribocorrosion tests, using a reciprocal tribometer, three electrochemical methods for monitoring tribocorrosion processes were used: firstly, a method for the monitoring of potential, secondly a potentiostatic method, and thirdly electrochemical noise measurements. Data about the total wear rate and individual contributions were obtained and evaluated. It was found that the NiTi alloy wire became more quickly worn, compared to the stainless steel wire, due to the alloy's hardness and different microstructural properties / oxide layer. The mechanical contribution to the total wear rate was higher in the case of the NiTi wire. The composition and differences between the base and newly formed oxide layer were determined by means of XPS/AES analysis. The ion release of wires exposed to simulated saliva was observed by ICP-MS analysis. The concentrations of metal ions decreased with exposure time, and the concentration of Ni did not exceed the limit values set by the EU Directive, i.e. 0.5 μg/cm2 × (7d). The concentrations of metal ions which could be transferred into the human body were monitored in the tribocorrosion experiments by means of simulated 1-day wear tests. It was found that in the case of the NiTi wire the concentration of Ni exceeded the value prescribed by the EU directive by a factor of 134, whereas in the case of the stainless steel wire this factor amounted to 65.
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